The tooth profile interlocking clearance, and in particular the torsional backlash, is known to create a hydrodynamic lubrication, compensating for dimensional changes caused by temperature effects, preventing abrasion or premature wear of the shaft, axles and toothed gears, and compensating bad construction and assembly work.
In the serial production of engines, gears or other aggregates, the adjustment of the tooth backlash of two or more toothed gears in mesh (serrated, helical, or other) pressed, screwed or secured otherwise onto driven or secondary shafts, requires elaborate alignment equipment or alignment devices.
DE 1 180 596 B, for example, describes a transmission with a device for adjusting the tooth flank backlash, axially displacing the conical toothed gears against one another depending on certain parameters of the gear transmission, thus adjusting the tooth backlash depending on the rotational frequency, temperature or stress.
DE-OS 2 020 722 provides for a wedge-shaped design of the teeth of toothed spur pinion gears allowing for an adjustment of the tooth flank backlash by axially displacing a toothed gear.
A common suggestion for adjusting the tooth flank backlash is known, e.g. from DE-PS 650 754, whereby one of the shafts of the interlocking toothed gears is stored in an adjustable eccentric bush, which is fastened relatively to the enclosure when trying to obtain the desired flank backlash.
DE 197 50 286 A1 also provides for eccentric elements in gear transmissions for compensating shafts of internal combustion engines. This provides for a movable and securable tooth flank backlash adjustment of the storage frame by means of the eccentric elements relatively to the rest of the machine enclosure the adjustment of the tooth flank backlash between a first gear located on the crankshaft-side and an intermediate or second gear located in a frame of the compensating bearings and interlocked with a driving gear of the compensating shafts. This assembly allows to adjust the tooth flank backlash between no more than two toothed gears.
DE-PS 883 379 describes a toothed rack-toothed quadrant gear transmission comprising a tooth flank-like clearance in at least one tooth flank in one of the final positions in order to avoid tooth flank backlash.
Furthermore, Niemann and Winter, “Maschinenenlemente (Machine Elements),” volume II, 2nd edition, p. 365, states that the flank backlash can be reduced to almost zero by copper plating the teeth of a toothed gear.
It is known from JP 560 24 257 that the backlash between toothed gears of a decimal gear pump can be set by applying a coat which is removed during operation.